Handle for a power tool

ABSTRACT

A hand-held power tool, in particular an angle grinder, includes a housing ( 4 ) having, at its working tool side end, a tool head ( 6 ) to which a working tool ( 10 ) is secured; a main handle ( 14 ) connected to the housing ( 4 ) at its handle side end remote from the working tool side end of the housing ( 4 ), rotatable about a rotational axis (B), and having an adjustably inclined relative to the rotational axis (B).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a motor-driven hand-held tool, in particular an angle grinder, having a housing which is provided, at its working tool side end, with a tool head to which a working tool, in particular, a disc-shaped tool is secured. At its handle side end remote from the working tool side end, the housing is connected with a main handle that rotates relative to the housing about a rotational axis.

2. Description of the Prior Art

Hand-held power tools of the type described above can be used, due to the adjustable main handle, in different applications, with the main handle being rotated or pivoted relative to the housing. Under the term “main handle,” such a handle is understood which, e.g., contrary to an additional side handle, which is put in, if necessary, is provided on the power tool for a lasting use and is gripped with an operator's hand at each conceivable use of the power tool.

German Publication DE 4102483 discloses an angle grinder in which the main handle rotates relative to the motor housing about its longitudinal axis. The motor housing has a support stud on which a turnstile, which is fixedly connected with the main handle, is rotatably held. There is further provided a locking device that insures a formlocking connection of the turnstile with the motor housing.

A drawback of the prior art power tool consists in that for some applications, despite presence of the rotatable support of the main handle, no ergonomically favorable gripping of the handle is possible. Thus, e.g., at works in the floor or overhead regions, the handle-holding hand is twisted outwardly or is rotated by a large angle. This can result in a hand injury and/or in rapid fatigue of the operator.

Accordingly, an object of the present invention is a hand-held power tool in which the above-mentioned drawbacks of conventional hand-held power tools are eliminated.

Another object of the present invention is a hand-held power tool with which an ergonomically favorable gripping of the main handle is possible at a large number of different applications.

SUMMARY OF THE INVENTION

These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a hand-held power tool the main handle of which in addition to rotation about a rotational axis, is also can be adjustably inclined to the rotational axis. Thereby, in addition to an adjustable rotational position, the inclination of the main handle relative to the housing can be changed. In this way, numerous possibilities of arrangement of the handle relative to the housing are obtained. Thus, for a particularly large number of possible applications of the hand-held power tool, an ergonomically favorable gripping of the handle becomes possible.

According to a particularly advantageous embodiment of the present invention, the inclination of the handle is adjusted by displacing the handle along an arch-shaped displacement path. Thereby, the handle pivots relative to the housing upon being displaced along its displacement path. The displacement along the arch-shaped displacement path insures a particularly stable support of the handle. In addition, a particularly large number of different inclination positions between the handle and the housing are obtainable.

Advantageously, the arch-shaped displacement path lies, in each rotational position of the handle about the rotational axis, in a plane that extends parallel to the rotational axis. In this way, the handle is adjusted, on one hand, about a rotational axis and, on the other hand, about an axis, stationary or virtual, which extends perpendicular to the rotational axis, whereby an ergonomically favorable gripping of the handle can be achieved almost at any conceivable application of the power tool.

Advantageously, the arch-shaped displacement path is defined by a connection device that connects the handle with the housing. The connection device includes a slide support on which an arch-shaped member is displaceably held. The arch-shaped member can be fixedly secured to the support with a locking device. Thereby, a stable guidance and a fixed connection of the arch-shaped member with the slide support is achieved.

Advantageously, the handle is D-shaped, with arch-shaped member being formed by the arch-shaped section of the handle. The integral formation of the handle with the arch-shaped member insures a particularly stable attachment of the handle to the housing at low manufacturing costs.

Advantageously, a releasable formlocking connection is provided between the arch-shaped member and the locking device, which connection is established in the direction of the arch-shaped displacement path. This permits to reliably secure the handle relative to the housing in different positions with a very small motion backlash.

It is particularly advantageous when the formlocking connection is formed by an engagement element of the locking device that is preloaded against the arch-shaped member and engages in one of a plurality of engagement recesses formed in the arch-shaped member. In this way, the formlocking connection can be easily formed and released.

According to a further particularly advantageous embodiment of the present invention, the handle is rotatably secured to the housing and is formlockingly secured thereto, without a possibility of rotation relative to the housing, by a safety or securing device. The safety device insures a stable support of the handle on the housing in a plurality of rotational positions about the rotational axis.

Preferably, the handle is secured by a connection device to a support member rotatable relative to the housing. The support member is connected to the housing by a safety element which forms part of the safety means, is preloaded against the housing, and engages in one of a plurality of safety recesses formed on the housing. The support member provides many possibilities for a stable and variable attachment of the handle to the housing. Further, for securing of the support member to the housing the same elements can be used which are used for securing the arch-shaped member to the support member. This further reduces manufacturing costs of the hand-held power tool.

The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show:

FIG. 1 a side view of a hand-held power tool according to the present invention;

FIG. 2 a side, partially cross-sectional view of the main handle of the hand-held power tool shown in FIG. 1; and

FIG. 3 a side partially cross-sectional view of the main handle of FIG. 2 in a pivotable, by 90° position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A hand-held power tool 2, which is shown in FIG. 1 and is formed as an angle grinder, has a housing 4 that forms, at its working tool side end, a tool head 6 with a working tool holder 8 for supporting a working tool 10 in form of a disc is provided.

At a handle side end of the housing 4 remote from the working tool side end of the housing, there is provided a support member 12 secured on the housing 4 with a possibility of rotation about a rotational axis B in a rotational direction D. The axis B coincides with the main axis of the substantially cylindrical housing 4.

The support member 12 permanently connects a D-shaped main handle 14 with the housing 4. The main handle 14 can rotate, together with the support member 12, about the axis B to a different rotational position relative to the housing 4, as shown with dash-dot lines.

The main handle 14 is formed essentially of a grip member 16 and an arch member 18 as a one-piece part. The arch member 18 is held on the support member 12 with a possibility of displacement along its longitudinal extent, so that the main handle 14 is positively guided upon displacement along an arch-shaped displacement pat P. The displacement path P is so aligned that it lies a plane E that independent from a rotational position of the support member 12 relative to the housing 4, always extend parallel to the axis B.

Because of a circular shape of its arch member 18, the main handle 14 would rotate about a fixed axis A upon being displaced, changing its inclination position relative to the housing 4, as shown with dash lines. Alternatively, the arch member 18 can have a shape that deviates from a circular profile. In this case, the main handle would rotate, upon being displaced, about a virtual, i.e., displaced, upon displacement of the main handle 4, rotational axis A.

As shown in FIG. 2, the main handle 14 is held by the arch-shaped member 18 in a guide channel 22 that functions as a slide support. The guide channel 22 forms, together with the arch member 18, a connection that defines that displacement path P of the main handle 14 relative to the support member 12.

The connection includes a locking device designated generally with a reference numeral 24. The locking device 24 has an engagement element 26 in form of a grooved block that is preloaded against the arch member 18 with a spring 28 which is supported against the support member 12. The engagement element 26 engages in one of plurality of recesses 30 which are formed in the arch-shaped member 18. Thereby a formlocking connection is obtained between the main handle 14 and the support member 12 in the direction of the displacement path P.

In order to release the formlocking connection, the engagement element 26 is connected with an actuation member 32 accessible from outside and with which the engagement element 26 can be withdrawn form the engagement recess 30 against the biasing force of the spring 28. After the engagement element 26 has been withdrawn from a respective recess 30, the arch-shaped member 18 can be displaced along the displacement path P in the guide channel 22. As a result, the main handle 14 would pivot about the rotational axis A to a new inclination position relative to the housing 4, as shown in FIG. 1 with dash lines. As soon as a desired inclination of the grip member 16 relative to the housing 4 which is particularly ergonomically favorable for the intended use of the power tool, is achieved, the actuation member 32 is released. As a result, the engagement element 26 would engage, under the action of the biasing force of the spring 28, in the engagement recess 30, again providing a formlocking connection between the main handle 14 and the support member 12.

As further shown in FIG. 2, there is formed, on the housing 4, a support stud 34 with a collar 36. The collar 36 is engaged form behind by an inwardly projecting rim 38 of the support member 12. This enables a rotational support of the support member 12 on the housing 4 in the rotational direction D.

In order to fixedly secure the support member 12 on the housing 4, without a possibility or rotation of the support member 12 relative to the housing 4, there is provided a locking device 40 that is substantially similar to the locking device 24, as can be seen in FIG. 3. The locking device 40 has a safety element 42 in form of a grooved block that is preloaded against the housing 4 by spring 44 and engages in one of a plurality of circumferentially arranged, safety recesses 46 formed on the housing 4. The formlocking engagement of the safety element 42 in a respective safety recess 46 provides for a formlocking connection between the support member 12 and the housing 4 in the rotational direction D.

For releasing the locking device 40, there is provided, in the surface of the support member 12, a recess 48 in which a release element 50, which is connected with the safety element 42, is displaceable. By actuating the release element 50, the safety element 42 can be displaced against a biasing force of the spring 44 out of the respective safety recess 46.

Upon release of the locking device 40, the support member 12 can be pivoted, together with the main handle 14, about the rotational axis B to a new rotational position relative to the housing 4. Upon reaching the desired position, the support member 12, together with the main handle 14, is locked in its new position by the safety element 42 engaging in a corresponding safety recess 46.

As further shown in FIGS. 2-3, there are formed in the arch member 18, two arcuate guide grooves 52 that cooperate with correspondingly formed ribs 54 of the guide channel 22. This insures a stable guidance and connection of the main handle 14 with the support member 12.

Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is not to be construed as a limitation thereof, and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiment within the spirit and scope of the present invention as defined by the appended claims. 

1. A hand-held power tool, comprising a housing (4) having, at a working tool side end thereof, a tool head (6) to which a working tool (10) is secured; a main handle (14) connected to the housing (4) at a handle side end of the housing (4) remote from the working tool side end of the housing (4) and rotatable about a rotational axis (B); and means for changing inclination of the main handle (14) relative to the rotational axis (B).
 2. A hand-held power tool according to claim 1, wherein the inclination changing means comprise means defining an arch-shaped displacement path (P), with the inclination of the main handle (14) relative to the rotational axis (B) being changed upon displacement of the main handle (14) along the arch-shaped displacement path (P).
 3. A hand-held power tool according to claim 2, wherein the displacement path (P) lies in a plane (E) extending parallel to the rotational axis (B).
 4. A hand-held power tool according to claim 2, wherein the arch-shaped displacement path-defining means is formed as connection means for connecting the main handle (14) with the housing (4), the connection means comprising a slide support for displaceably supporting an arch-shaped member (18) and locking means (24) for securing the arch-shaped member (18) on the slide support.
 5. A hand-held power tool according to claim 4, wherein the main handle has a D-shape, and wherein the arch-shaped member (18) is formed by an arch-shaped section of the main handle (14).
 6. A hand-held power tool according to claim 4, wherein the locking means further comprises releasable formlocking means for releasably formlockingly connecting the locking means (24) with the arch-shaped member (18) in a direction of the arch-shaped displacement path.
 7. A hand-held power tool according to claim 6, wherein the formlocking means comprises an engagement element (26) engageable in one of a plurality of engagement recesses formed in the arch-shaped member (18).
 8. A hand-held power tool according to claim 1, comprising means providing for rotation of the main handle (14) relative to the housing (4), and means (40) for formlockingly securing the main handle (14) to the housing without a possibility of rotation of the main handle (14) relative to the housing (4).
 9. A hand-held power tool according to claim 8, wherein the rotation providing means comprises a support member (12) for holding the main handle (14) and rotatable relative to the housing (4), and the formlocklingly securing means (40) comprises a safety element (42) preloaded against the housing (4) and engageable in one of a plurality of safety recesses (46) formed on the housing (4). 